The invention herein resides generally in the art of concrete building structures. More particularly, the present invention relates to spans across long distances, utilizing in-situ forms. Specifically, the present invention relates to a structure that facilitates stressing of concrete spans. This is accomplished by installing cables into a form and then placing them under tension against cast-in-place concrete or an external form support. Next, the concrete is poured into the form around the cables. Once the concrete has set, the tension in the cable is released for transfer into the span.
There are two commonly-used methods for forming long-span concrete structures such as bridges, parking decks, building floors, structures within stadiums, and the like. These structures may be made by either using pre-cast pieces which are manufactured offsite, and then transported to the construction site and assembled. Alternatively, these structures can be manufactured by building the forms on site, pouring concrete into the forms and then removing the forms.
The pre-cast method utilizes standard or special forms which receive concrete or other structural building-type material. After an appropriate curing time, the form is opened and the piece is removed. Reinforcing members may be included in the form if desired. Utilizing such forms allows the manufacturer to efficiently build a large number of building components to a particular specification depending upon end-use. Although this method is effective, there are high costs involved in shipping and erecting the pre-cast pieces. Additionally, the cost of craning the large weight of pre-cast pieces into place adds significant extra cost to high-rise structures.
The other common method for forming long-span concrete structures is where the forms are assembled on site with the desired reinforcing structure. In some instances, significant site preparations are required. Next, the concrete is poured into the form, and after it has set, the forms are removed. This method is also costly inasmuch as the site must be properly prepared to accommodate the form and supporting structure and then the supporting structure must be torn down, cleaned and removed or reinstalled after completion of the concrete pour and setting thereof. Forming the concrete members in place is quite expensive for highly-engineered structures such as bridges, stadiums, and high-rise structures.
Although these known methods are effective in providing high-quality building structures, it is submitted that their cost is excessive and somewhat time-consuming in preparation. Moreover, the concrete is ultimately exposed to the elements which contributes to the deterioration of the entire structure. Current construction methods do not adequately provide a reliable and easy low-cost way to build long-span concrete structures. Nor do current methods provide protection to the concrete material after it has set.
In light of the foregoing, it is a first aspect of the present invention to provide a long-span in-situ concrete structure and method for constructing the same.
It is another aspect of the present invention to provide a long-span concrete structure extending between supporting structures such as beams, walls, piers, and the like.
It is a further aspect of the present invention to provide for the in-situ forming of long-span structures, as set forth above, which are assembled on site, are cost effective to assemble, and provides significant protection from natural elements upon completion of the construction.
It is yet another aspect of the present invention to provide a long-span concrete structure, as set forth above, in which a form support extends between and is coupled to the supporting structures.
It is still another aspect of the present invention to provide a long-span structure, as set forth above, which utilizes a form hanger that is frictionally assembled to the form support along the length thereof between the supporting structures.
It is still a further aspect of the present invention to provide a long-span structure, as set forth above, to suspend a beam form from the form hangers along the entire length of the form support between the supporting structures.
It is an additional aspect of the present invention to provide a long-span structure, as set forth above, to employ a form support positioned between the form support and the bottom of the beam form to maintain medial spacing between the form support and the beam form.
It is still yet another aspect of the present invention to provide a long-span structure, as set forth above, in which a deck form is assembled onto the top of the beam forms and supported thereby so as to receive concrete material within the beam form and on the deck so as to form the span between the supporting structures.
It is yet another aspect of the present invention to provide a long-span structure, as set forth above, wherein a deformed cable conduit is carried by the beam form and is capable of carrying a cable. The cable conduit precludes entry of the concrete material into the conduit during the assembly of the long-span structure. The conduit may be a single, double, or a plurality of tubes so as to allow for receipt of a cable in each one.
It is yet a further aspect of the present invention to provide a long-span structure, as set forth above, wherein the cable received within the conduit is tensioned or pre-stressed a predetermined amount against the previously poured and set concrete and whereupon concrete material is filled into the conduit. After setting of the concrete within the conduit, the tension applied to the cables is released so as to transfer the pre-stress from the cable to the initially poured concrete.
It is still yet a further aspect of the present invention, as set forth above, to provide mating hooks on the form hangers and the beam forms to assist in their assembly and wherein the beam forms are made of a plastic or polymeric material which protects the concrete after it has taken a set.
In a variation of the present invention, it is another aspect to provide the beam forms with side supports between the supporting structures.
It is another aspect of the present invention, as above, to configure the side supports such that they are braced to each other to maintain proper spacing therebetween and assist in carrying the beam forms.
It is still another aspect of the present invention, as above, to provide a tension plate at each end of the beam form to assist in tensioning cables placed in the beam form against the side supports, prior to receipt of concrete therein.
It is yet another aspect of the present invention, as above, to position the form support horizontally in the beam form and provide pegs vertically extending from the form. After the setting of the concrete within the form, the tension applied to the cables is released so as to transfer the stress from the cables to the span.
The foregoing and other aspects of the present invention, which shall become apparent as the detailed description proceeds, are achieved by a long-span concrete structure extending between supporting structures, comprising at least one form support extending between the support structures, and at least one beam form carried by the support structures and partially enclosing the corresponding form support, wherein concrete is receivable in said beam form to form the long-span concrete structure.
The present invention also provides a long-span structure formed in-situ and extending between supporting structures, comprising at least one form support extending between the supporting structures, wherein each end of said form support includes a bearing plate coupled to the adjacent supporting structure, a plurality of form hangers frictionally engaging said form supports, each said form hanger having upwardly extending hooks, and a beam form carried by said plurality of form hangers and extending the length of each said form support, each said beam form having opposed side walls connected by a bottom to form a cavity, each sidewall having a downwardly extending hook mating with said upwardly extending hooks, wherein concrete is receivable at least in said beam form cavity to form the long-span structure.
The present invention further provides a method for constructing a long-span structure, comprising the steps of providing at least two supporting structures spaced a distance apart from each other, spanning said distance with at least one form support, supporting at least one beam form for each said form support and extending the entire length thereof, each said beam form having a cavity, and pouring concrete into said cavity to form the long-span structure across the distance.
These and other aspects of the present invention, as well as the advantages thereof over existing prior art forms, which will become apparent from the description to follow, are accomplished by the improvements hereinafter described and claimed.